Terminal holder, battery module and method for producing same

ABSTRACT

A terminal holder is provided for holding a connection terminal ( 20 ) for at least three round cells ( 14, 15, 16 ). The terminal holder has a centrally encircling rib ( 11 ) for placement of the terminal holder ( 10 ) on the round cells ( 14, 15, 16 ) and for spacing the connection terminal ( 20 ) apart from the round cells ( 14, 15, 16 ). An elastic lip ( 12 ) is arranged at the end for clamping the terminal holder ( 10 ) between the round cells ( 14, 15, 16 ). A plastic head ( 13 ) is arranged opposite the lip ( 12 ), for fastening the terminal holder ( 10 ) on the connection terminal ( 20 ).

CROSS REFERENCE TO RELATED APPLICATION

This application claims priority under 35 USC 119 to German Patent Appl.No. 10 2014 109 054.3 filed on Jun. 27, 2014, the entire disclosure ofwhich is incorporated herein by reference.

BACKGROUND

1. Field of the Invention

The invention relates to a terminal holder, a battery module equippedwith a terminal holder and to a method for producing a battery module ofthis kind.

2. Description of the Related Art

The term “electric vehicle” commonly includes any means of transportthat is driven by electric energy. The above designation thus includesroad vehicles, especially motor vehicles, rail vehicles, watercraft andaircraft. A “hybrid vehicle” has the electric drive combined withanother drive. Energy required for driving that cannot be suppliedcontinuously from outside is stored in the vehicle itself by suitable“traction batteries”. According to the prior art, such tractionbatteries are typically of modular construction, where each batterymodule can comprise secondary cells, generally of round construction.U.S. Pat. No. 8,642,203 B2, DE 10 2008 034 878 B4 and DE 10 2008 059 972A1 disclose round cell accumulators of this type.

Another known practice is to connect respective poles of a number ofbattery cells to one another by means of a conductive board or a metalsheet. This component can serve as a connection terminal to contact allthe battery cells of a battery module over an extended area. DE 10 2009035 487 A1 describes an arrangement of this kind. However, themechanical holding of the terminal proves problematic. In this respect,DE 10 2011 009 768 A1 proposes to weld or solder corresponding rail- orplate-shaped elements to the cells. Nevertheless, this gives rise totolerances that have to be compensated for by additional measuresaccording to the prior art.

In view of the above, an object of the invention is to fix a connectionterminal reliably on an assembly of battery cells. A further object isprovide a battery module and a method for producing a battery module ofthis type.

SUMMARY OF THE INVENTION

The invention relates to a battery module with round cells and aterminal holder that employs a combination of non-positive and positiveconnection techniques. At the same time, the proposed device supports aparticularly uncomplicated manufacturing method, in which a terminalholder is inserted between three round cells and centers itself in alargely automatic way through the elasticity of its lip. Thesefunctional and procedural advantages allow a considerable lowering ofunit costs as compared with conventional battery modules.

The development enables an introduction of a terminal holder between theround cells at any conceivable center angle by exploiting the rotationalsymmetry of the main body.

The terminal holder may be of integral construction thereby furtherreducing the complexity of the production process.

An insulator may be disposed between the round cells and the connectionterminal. The insulator may be a polymer, such as a polyamide and may befiber reinforced for additional strength, rigidity and toughness, whileensuring resistance to chemicals.

The round cells may be encapsulated with a potting compound after theterminal holder has been clamped to achieve high stability and sealingwith a low weight.

An illustrative embodiment of the invention is shown in the drawings andis described in detail below.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of a terminal holder according to theinvention.

FIG. 2 illustrates a production method of the invention in a firstphase.

FIG. 3 illustrates the production method in a second phase.

FIG. 4 illustrates the production method in a third phase.

FIG. 5 illustrates the production method in a fourth phase.

FIG. 6 is a perspective section through a battery module of theinvention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

A terminal holder according to the invention is identified by thenumeral 10 in FIG. 1. The terminal holder 10 is of unitary or integralconstruction and has a substantially cylindrical main body with acentrally encircling rib 11 and an elastic lip 12 molded at one end. Ahead 13 is defined at the end of the main body opposite from the lip 12.

The terminal holder 10 may be formed from a polyamide with DINabbreviation PA 66 GF 30 and with a glass fiber content of 30%. However,an alternative embodiment may use of an unreinforced polyamide or someother nonconductive polymer that has the ductility and suitability formolding required for the respective use.

FIGS. 2 to 5 illustrate the use of the terminal holder 10 in the contextof a method according to the invention for producing a battery modulefor a hybrid or electric vehicle. As shown in FIG. 2, the battery modulefor storing electric energy comprises an assembly of many round orcylindrical cells in a hexagonally ultracompact cylinder package. Theproposed method will be explained purely by way of example below bymeans of three round or cylindrical cells 14, 15, 16 in a triangulararrangement, wherein the steps now described could be applied to allsuch arrangements within the battery module.

As FIG. 2 shows, the terminal holder 10 initially is alignedapproximately axially parallel to the round cells 14, 15, 16 and ispositioned approximately vertically over the centroid of the triangleformed by the poles thereof so that the lip 12 faces in the direction ofthe round cells 14, 15, 16 and the head 13 faces away therefrom. Fromthis approximate initial position, any deviations are compensated for bythe features of the terminal holder 10, as explained herein. Theterminal holder 10 can be introduced largely vertically into theinterstices between the round cells 14, 15, 16, and parallel to thelongitudinal axes thereof. The movement in this direction is effectivelylimited by the rib 11 as soon as the rib is resting on the end faces ofthe round cells 14, 15, 16, so that only the head 13 is still projectingfrom the assembly. This vertical end position of the terminal holder 10is shown in FIG. 3.

The pairwise contact between the round cells 14, 15, 16 requires thatthe circumferential surfaces thereof should pose a mechanical resistanceto the penetration of the terminal holder 10, said resistance beingdependent on the diameter of the lip 12 of the terminal holder 10. Inthis phase, the elasticity of the lip 12 is decisive and enables the lip12 to adapt to the cavity remaining between the round cells 14, 15, 16.At the same time, the resiliently deformed lip 12 exerts a uniformrestoring force with three equiangular direction components on theterminal holder 10 to achieve a clamped elastically between the roundcells 14, 15, 16.

As shown in FIG. 4, the round cells 14, 15, 16, together with the lowerregion of the terminal holder 10 clamped in this way, then areencapsulated with a potting compound 17. A connection terminal 20 withthree equidistant apertures 24, 25, 26 can then be placed on the endfaces of the round cells 14, 15, 16 so that a central, fourth hole 23accommodates the head 13 of the terminal holder 10 that projects fromthe assembly, placement preferably taking place only after the curing ofsaid potting compound 17. Of course, the connection terminal 20 may haveconsiderably more apertures to match a corresponding multiplicity ofround cells 14, 15, 16 and terminal holders 10. In this case, the heads13 interact with the corresponding apertures 23 to functionsimultaneously as a positioning aid for the terminal holder 10 and theconnection terminal 20. The apertures 24, 25, 26 need not be ofhollow-cylindrical design and aligned coaxially with the round cells 14,15, 16. FIG. 5 reflects the temporary final state of this method step,as a consequence of which only the head 13 of the terminal holder 10projects from the hole 13 in the connection terminal 20.

In a final method step, preferably under the action of heat, the head 13of the terminal holder 10 is plastically deformed and, as FIG. 6illustrates in conjunction with FIG. 5, is pressed flat onto theconnection terminal 20 over the edges of the hole 13. The head 13, whichis now also connected positively to the connection terminal 20perpendicularly to the axis of the terminal holder 10, thus fastens theconnection terminal 20 finally on the terminal holder 10, where it canserve for contacting the round cells 14, 15, 16 during the operation ofthe battery module.

What is claimed is:
 1. A terminal holder for holding a connectionterminal for at least three round cells, comprising: a centrallyencircling rib for placement on the round cells and for spacing theconnection terminal apart from the round cells; an elastic lip, arrangedat an end for clamping the terminal holder between the round cells; anda plastic head arranged opposite the lip, for fastening the terminalholder on the connection terminal.
 2. The terminal holder of claim 1,further comprising a substantially cylindrical main body extendingbetween the elastic lip and the plastic head.
 3. The terminal holder ofclaim 2, wherein the terminal holder is of integral construction and therib and the lip are molded onto the main body.
 4. The terminal holder ofclaim 3, wherein the terminal holder is made of a nonconductivematerial.
 5. The terminal holder of claim 4, wherein the nonconductivematerial contains a polymer.
 6. The terminal holder of claim 5, whereinthe polymer is a polyamide.
 7. The terminal holder of claim 6, whereinthe polyamide is glass fiber reinforced.
 8. A battery module for ahybrid or electric vehicle, comprising: at least three round cells forstoring electric energy; a connection terminal resting on end faces ofthe round cells for electrically contacting the round cells, theconnection terminal having at least three equidistant apertures; and atleast one terminal holder for holding the connection terminalmechanically on the round cells, the terminal holder having a centrallyencircling rib for placement on the round cells and for spacing theconnection terminal apart from the round cells, an elastic lip, arrangedat an end for clamping the terminal holder between the round cells, anda plastic head arranged opposite the lip, for fastening the terminalholder on the connection terminal.
 9. A method for producing a batterymodule using the terminal holder of claim 1, comprising: placing the ribof the terminal holder on at least three round cells; using the lip forclamping the terminal holder elastically between the round cells; andplastically deforming the head of the terminal holder on the connectionterminal.
 10. The method of claim 9, further comprising: encapsulatingthe round cells with a potting compound after the terminal holder hasbeen clamped, and fastening the terminal holder on the connectionterminal after the potting compound has cured.
 11. A method forproducing a battery module, comprising: positioning at least three roundor cylindrical battery cells so that longitudinal axes thereof aresubstantially parallel and so that terminals thereof face in a commondirection; providing at least one terminal holder having an elongatemain body with opposite first and second ends, an elastic lip inproximity to the first end, a head in proximity to the second end, andan encircling rib between the first and second ends; moving the elasticlip into an interstices between the battery cells so that the elasticlip is deformed resiliently by the battery cells; stopping movement ofthe terminal holder when the encircling rib contacts the battery cells;mounting a terminal plate on the battery cells and the terminal holderso that the head of the terminal holder passes through a hole in theterminal plate and so that the terminals of the battery cells registerwith apertures in the terminal plate.
 12. The method of claim 11,further comprising placing a potting material into areas of theinterstices between the battery cells and surrounding the main body ofthe terminal holder prior to mounting the terminal plate on the batterycells and the terminal holder.
 13. The method of claim 12, furthercomprising curing the potting material prior to mounting the terminalplate.
 14. The method of claim 11, further comprising plasticallydeforming the heads of the terminal holder into engagement with theterminal plate.